notes. >> how do you keep your records? how do you know what's been here? >> i have a running log right here that i keep. >> reporter: other club members add their observations to the notebook under the bench. from september 2007. >> we had ten common checkered skippers and -- >> this is a southern species. >> yes. >> reporter: this year, the buzz is all about the giant swallow tails, common in the deep south. >> have you ever seen 108 giant swallow tails in a season? >> not in my whole life. never mind a whole season. >> reporter: some may consider these club members too, accidentals too, accidental scientists, not breed. >> if they go out and look and they're interested, and they write what they see, that's a perfectly valid observation. >> reporter: seeing nature's patterns change right before their eyes. anne thompson, nbc news, northampton, massachusetts. >> that is our broadcast on a tuesday night. thank you for being here with us, i'm brian williams, we sure hope to see you right back here with us tomorrow evening.